The present invention relates to a method of controlling an automotive engine and in particular to a method of stopping a parallel hybrid engine while anticipating restarting the engine.
Automotive vehicle powertrains incorporate engine start/stop (ESS) systems to improve fuel economy. ESS stops an internal combustion engine under specified conditions when engine torque is not required and restarts the engine when torque is again required. For example, ESS may stop the engine of a vehicle after a driver brakes the vehicle to a stop at a traffic light and then restart the engine when the driver requests torque by depressing an accelerator pedal when the traffic light changes. ESS is commonly incorporated into hybrid electric powertrains. The more conditions specified when ESS stops the vehicle engine, the greater the potential improvement to fuel economy.
However, restarting an ESS stopped engine has a time delay. This delay may decrease the drivability of the vehicle. The delay may be more pronounced when the driver requests torque while the engine is still in the process of being stopped. Under certain scenarios the engine may be controlled to complete its stop routine before commencing its restart routine.